Perfecting offset press



July 18, 1950 H. A. PRITCHARD momma oFFsE'r mass 2 Sheets-She 1 FiledJuly 13, 1945 IIYVVENTOR. l/awneo A PE/TCHABD 2% 1W B M 7m HT ORNEYJJuly 18, 1950 H. A. PRITCHARD PERFECTING OFFSET PRESS 2 Sheets-Sheet 2Filed July 13, 1945 INVENTOR. 190M420 A PE/TCHAQD BY 7km W15 HTTOR/VE Y5Patented July 18, 1950 rsarncrmo OFFSET-PRESS Howard A. Prltchard,Hiram, Ohio, assignor to Harrls-Seybold Company, Cleveland, Ohio, a

corporation oi Delaware Application July 13, 1945, Serial No. 604,955

4 Claims.

This invention relates to improvements in perfecting ofiset presses andhas to do primarily with the arrangement of the plate and blanketcylinders of the two printing units symmetrically, and such dispositionof other parts that relatively large areas of those cylinders areexposed on the outer sides of the units for most convenient access bythe operators, the invention providing also that each pair of plate andblanket cylinders shall turn in the same direction relative to theadjacent working space for the convenience of the men working on thepress.

One of the objects of the invention is the provision of a press in whichthe cylinders of the two units are so disposed and so interconnected bythe driving means that two operators may be engaged simultaneously inperforming identical work upon the two units, thereby facilitating andexpediting the preparation of the machine for printing.

Another object is the provision of a perfecting press of the characterstated wherein the inkers may be disposed above the plate cylinders, inother words in their most advantageous positions, and yet leave theplate cylinder and blanket cylinder adequately accessible.

Other objects and features of novelty will appear as I proceed with thedescription of those embodiments of the invention which, for thepurposes of the present application, I have illustrated in theaccompanying drawings, in which Fig. 1 is a diagrammatic view partiallyin side elevation and partially in vertical section of an ofisetperfecting printing press embodying my sent the plate, blanket andimpression cylinders V which is symmetrical with that of the lattercylinders. Consequently, the base or longest leg of the triangle, thepoints of which are cut by the axes of the cylinders l3, l4 and I5,faces in the direction of the similar leg of the triangle firstmentioned.

In order to space the two printing units apart far enough to providesufilcient room between them and to reverse the sheets for printing onthe opposite sides, I employ two transfer cylinders i6 and IT. Thecylinders i2, i5, I6 and II are all provided with conventional sheetgrippers and gripper operating means of known character in order thatthe sheets printed on one side may be accurately transferred and thesecond printing caused to occupy a position on the sheet correspondingto that of the first printing.

The means which I employ for feeding sheets to the press is soconstituted as to deliver sheets to the grippers of cylinder l2 at apoint below the axis of that cylinder and on the side thereof which isnearest the blanket cylinder ii. For this purpose I have shown hereindiagrammatically a feed table i8 over which sheets are carried by tapesl9 from a pile 20. After the usual front and side registration by meansnot shown,

the sheets are taken by the grippers on a feed.

cylinder 2i and transferred therefrom to the grippers of a second feedcylinder 22 which delivers them to the grippers of impression cylinder82.

An operators platform 23 may be disposed above the feed table inconvenient relation to the cylinders i0 and ii, and if desired may behinged at one end upon a cross rod 2 in order that when it is not in useit may be swung up out of the way to expose to view and renderaccessible the feed table and the sheets moving thereover After thesheets have received an imprint from the second unit they are taken bygrippers on a transfer cylinder 25 and transferred to travelin grippers26 on a chain delivery 21 which carries the sheets upwardly and thenover the top of the second unit and down to a delivery pile 28.

The inkers for the first and second units of the press are indicatedgenerally by the reference numerals 30 and 3!. They are disposed abovethe respective plate cylinders i0 and i3, but substantially upon theinner sides of planes through the axes of cylinders I 0 and ii of theone unit and I 3 and M of the other, these planes being indicated in thedrawings by the lines 32 and 33 respectively. This disposition of theinkers enables them to partake of the well-known advantages of inkersarranged over the plate cylinders, while at the same time permitting thedampening mechanisms 34 and 35 to be disposed well above the axes of theplate cylinders. Hence the outer surfaces of the two pairs of cylindersIII, II and l3, H are almost fullyexposed and therefore easily reachedand worked upon by the operators. Furthermore, by reason of thedisposition of the various cylinders and the armay be identical with thecorresponding parts of the Fig. 1 construction, although the spacing ofthe two pairs of plate and blanket cylinders may be somewhat different.In this form however there are no separate transfer cylinders between Ithe two units.' The units have impression cylinders 36 and 31respectively of double size compared with the plate and blanketcylinders. Each of these cylinders has two sheet supporting sur- Themode of operation and the advantages of this second form of theinvention are substantially the same as in the case of the firstdescribed form.

Having thus described my invention, I claim:

1. In a sheet fed perfecting offset press; two printing units eachcomprising plate and blanket cylinders of the same size inverticalalignment and an impression cylinder of double size, theimpression cylinder of each unit being disposed below the axis of theblanket cylinder on the side thereof toward the other unit, theimpression cylinders of both units having two sets of sheet grippers,the impression cylinders and their grippers being so disposed that thegrippers of the first unit impression cylinder transfer sheetsdidirectly to the grippers of the second unit impression cylinder.

2. In a sheet fed perfecting offset press, first and second printingunits each comprising plate,

. blanket and impression cylinders, each unit being faces and two setsof grippers, the grippers of der may be transferred directly to thegrippers ll 9f cylinder 31, and a sheet taken by the grippers 38 may becorrespondingly transferred directly to the grippers 40. Therefore theimpression cylinders, in addition to performing their usual functions,in this case function also as transfer cylinders. As compared with thefirst form of the invention therefore, two cylinders with their bearingsand driving connections are eliminated and the machine is simplified tothat extent.

In this case the axes of the three cylinders of each unit cut the pointsof a triangle, but the triangle in this case is not an isoscelestriangle. However, as in the case of Fig. 1, the longest legs of the twotriangles face toward each other.

Feed cylinders 2| and 22 similar to the cylinders 2| and 22 of Fig. 1may be employed for transferring sheets from a feed board l8 to theimpression cylinder 36. The sheets after being imprinted on both sidesby the two units of the machine are taken by grippers on a transfercylinder 25' and transferred to grippers 26 on gripper bars formingparts of a chain delivery 21', all of these parts being similar to theparts 25, 26 and 21 of Fig. 1.

arranged with the plate cylinder above the blanket cylinder and theimpression cylinder on the side of the blanket cylinder toward the otherunit,

a sheet feed table arranged on the side of the first unit remote fromthe second printing unit, gripper means for conveying sheets receivedfrom the table under the first unit blanket cylinder to the first unitimpression cylinder, partly around each impression cylinder, upwardlybetween the plate cylinders and toward a delivery point, said grippermeans placing the sheets upon the first impression cylinder at a pointbelow its axis and removing the sheets from the second impressioncylinder at a point above the axis of the latter cylinder.

3. Mechanism as claimed in claim 2 wherein said sheet gripper meansincludes a'rotary gripper-equipped sheet handling cylinder between thefeed table and the first impression cylinder for placing the sheets uponthe latter.

4. Mechanism as claimed in claim 2 wherein said sheet gripper meansincludes two sets of moving sheet grippers between the feed table andthe first impression cylinder, one of which is adapted to place thesheets upon the first impression cylinder. I

HOWARD A. PRITCI-IARD.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Harris Oct. 1'7, 1944

